This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. AM2 is a homotetrameric, type III integral membrane protein containing a small N-terminal periplasmic domain (23 residues), a single transmembrane domain (20 residues), and a C-terminal cytoplasmic tail (53 residues). AM2 is activated at low pH and selective conduct proton over other cations like Na+, k+. AM2 is a proved drug target of amantadine/rimantadine in treating influenza infection for decades, but its effectiveness is greatly diminished by emerging drug resistant mutants in the transmembrane drug binding site like S31N, V27A, L26F etc. Understanding how the drug binds to AM2 and how drug binding and pH change affect the global conformation of AM2 is absolutely necessary for rational design of next generation anti-influenza small molecule drugs. Our goal is to get a structure assignment of AM2TM (19-49) in solution detergent micelle using 15N and 13C double labeled sample.